Warp knitting machine tensioning device



Sept' 151,Y `1953 c. J. BROWN ET A.; 2,651,930

WARP KNITTING MACHINE TENSIONING DEVICE Filed April 2, 1949 l l l M5 1 r l l AG INVENTORS.

A T TORNEY Patented Sept. 15, 1953 WARP KNITTING MACHINE TENSIONING DEVICE Clarence J. Brown and Theodore F. Schwanda, Bangor, Pa., assignors to Blue Ridge Textile Company, Inc., Bangor, Pa., a corporation of Pennsylvania Application April 2, 1949, Serial No. 85,106

16 Claims. 1

This invention relates to an improvement in a warp knitting machine tensioning device usually associated with a well known class of warp knitting machines wherein numerous warp yarns are fed from reels through yarn guides for manipulation into a warp knitted fabric by means of needles and other conventional knitting mechanisms. 4

In the class of machines referred to the yarns are drawn from the reels as they are required for each knitting cycle by the movement of the knitting mechanism. To avoid intermittent tugs upon the yarns, which would increase the danger of breakage and result in irregularities in the knitting operation and in the fabric itself, various means are employed to provide a smooth yarn feed. These generally resiliently support the yarn and employ the strain placed on the yarns as they pass from the reels to the knitting mechanism, to start and control the unwinding speed of the reels. The resilient yarn support between the reels and the knitting needles is the subject of the improvement herein described.

The resilient yarn support, sometimes called a yarn pilot or guide rod but herein referred to as a tension rod, is rendered resilient by suitably placed springs and as the yarns pass over its polished surface is responsive to the strain placed on the yarns just prior to each knitting cycle. When the machine is continuously operated this tension rod under spring action and in combination with the other reel controls serves its purpose in avoiding irregularities in operation and in the fabric. However, when for any reason the machine is stopped by the operator, it will be found that after again starting up operation the fabric will reveal the line at which such stoppage occurred. This is because upon stopping a certain amount of slack will be created in the yarns and the tension rod is incapable of maintaining the same uniform tension therein. When the mechanism begins operation, this difference in yarn tension is reflected during the first knitting cycle in the fabric.

The principal object of this invention is to eliminate such stop markings. A further object is to incorporate in a warp knitting machine means for anticipating and cushioning sudden application or release of tension upon the yarns. Other objects will appear from the description which follows.

In the accompanying drawings Figure l shows a side elevational view of a tension rod support.

Figure 2 shows an enlarged portion of the tension rod support bearing showing the cylinder in cross section.

Figure 3 is a diagram of the controls and pressure system associated with the tension rod supports.

Referring to the drawings in which the same number refers to the same or similar parts, the construction of one embodiment of this invention is as follows:

Tension rod 3, shown in side elevation in Figure 1, is the conventional polished rod used in a warp knitting machine of this type and is generally about one inch in outside diameter and running the length of the machine parallel with the axis of the yarn supply reels. Since this invention concerns itself with tension rod 3S supports, no further description of tension rod 3 appears necessary for a proper understanding of this improvement. Passing over tension rod 3 are a multiplicity of yarns I2, one of Which is shown in Figure I. When the knitting mechanism calls for more yarn a pull is exerted on yarns I2 and in response thereto tension rod 3 is resiliently displaceable, assuming a position between those shown in solid and dotted outline in Figure l.

Tension rod 3 is carried by two or more rock arms I which are pivotal about pivot rod 2, which in turn is supported on the frame of the machine. Rock arm I has opening 4 at its one end through which threaded guide rod 5 passes. This threaded guide rod 5 is pivotally secured to the frame of the machine with anchor 6 and is responsive to the movements of rock arm I.

About threaded guide rod 5 is coil spring 8, each end of which is capped by a washer 9. Over spring 8 is an air cylinder slidably mounted on threaded guide rod 5 consisting of cylinder barrel 'I and piston I3 with the usual auxiliary parts associated with a cylinder. Causing this cylinder and spring 8 to bear on rock arm I are adjustable thumb nuts lil threaded on guide rod 5.

Referring to Figure 2, the cylinder in cross section discloses the external surface of piston I3 bearing on washer 9 which in turn bears on spring 8. Packing I4 internal of the cylinder barrel and inlet I complete the principal features of the cylinder construction. To inlet I5 is connected hose connection II.

In the usual type of warp knitting machine there are generally two tension rods, one for each of two banks of reels, each supported by three rock arms. In Figure 3 is shown a control and supply system for providing a supply of compressed air to each of six rock arm cylinders. In Figure 3 these are shown with their connections II joined to a compressed air supply pipe IS which terminates at one end in bleed valve I'I. The compressed air sup-ply is derived from compressor 22 and the air is furnished through supply pipe I6, strainer ZI, pressure regulator 2li and three way solenoid valve I9 to the cylinders. Speed valve IS associated with valve I9 permits suitable adjustment to be made in the rate of exhaustion or bleeding of the cylinders. Operably connected with three way solenoid valve I9, electrical conductors 23 and conventional delay relays 2li, is the warp knitting machine motor circuit. As shown in Fig. 3, the knitting machine is' operated by a motor M connected to the A. C. lines through a starter circuit S. The starter circuit S is operatively connected to the time delay relays 2li and is provided with start and stop buttons for manual control of the motor l/I. With the motor circuit closed, valve I9 functions to withhold air from the cylinders and to open them out through speed valve I8 into the atmosphere. With the motor circuit open, valve is functions to close speed valve I8 and admit compressed air into the cylinders.

In Figures l and 2 the cylinder is shown in the position it will assume after air pressure been introduced into cylinder barrel l. When the pressure is relieved piston I3 is, under the action of spring 8, completely seated within cylinder barrel 1.

The mechanism functions in the following manner. While the warp knitting machine is operating in its customary fashion, compressed air is not present in cylinder barrel 'I and piston I3 is completely retracted within the barrel. The machine operator, as is customary, adjusts the working tension in yarns I2 by suitably moving thumb nuts i9. In such adjustment no consideration need be given to the presence of the cylinder, all of the required resilience needed by tension rod 3 being supplied by spring 8. When the operator pulls the machine motor circuit switch, delay relay 24 serves two functions. v It actuates valve I9 and also operates to postpone the cutting off of electric current to the machine motor while valve I9 is admitting compressed air into cylinder barrels 7 to the desired predetermined pressure. Pressures of from 20 to 30 pounds per square inch will be found vsatisfactory for the average installation, but should be established in harmony with the cylinder piston size and other elements of the system. This will promptly cause piston I3 to be forced outward, thus forcing tension rod 3 to rise against the yarns I2 and maintain a uniform tension in them. Thus when the machine stops and at the time the slack would otherwise occur in yarns I2 there is the added take-up provided by the action of the cylinders. When the machine motor switch is closed, current flowing through the motor circuit operates valve I9 through time delay relay 24, shutting off the air supply and bleeding the compressed air from all of the cylinders at a predetermined rate through speed valve IB a timed interval after the switch is closed. When the air has 4 escaped the resilience will be supplied only by spring 8.

The foregoing is but one example of the application of this improvement. On various types of warp knitting machines different arrangements for supporting tension rod 3 are found. The shape and location of rock arm I may vary and the place where spring tension is supplied may be diiferent in different machines. It is apparent, however, that this improvement may be incorporated in the several types of tension rod resilient supports. It is further noted that while this example has been given showing the use of compressed air it is possible, of course, to use any gas under compression or a liquid. Compressed lair is preferred because of its economy and because it does work faster than a liquid.

On some types of machines, for example in those wherein the electric motor is not braked to a stop, an electrical time delay may be dispensed with on the shutting down of the machine. When a carefully controlled rate of bleeding is established an electrical time delay may be dispensed -with as part of the machine starting operation. Thus in some machines time delay relays may not be needed.

The term cylinder when used in these specifications and claims refers to the complete unit, that is, the assembled piston and cylinder barrel. It need not follow the details shown herein but any suitable type may be used and interposed as part of the tension rod resilient support.

In the operation of this improvement it has been stated that while the machine is operating the cylinder is not under pressure. It is possible, however, to have some air pressure in each cylinder without losing the value of this improvement in the stopping and starting of the knitting machine. It is not intended by the description herein given to limit the scope of this invention since it is obvious that many mcdications may be made in the particular construction illustrated without exceeding the limits of the linventiorb What we claim is:

1. In a warp knitting machine having a resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing over it, means for yieldingly supporting said rod, and yarn tension sustaining means associated with said supporting means comprising a piston and piston chamber.

2. In a warp knitting machine having a resiliently displaceable tension rod responsive to variations of the pull of the yarns iiowing over it, yarn tension sustaining means associated therewith urging said tension rod against the yarns, said means including an enclosed chamber, means for introducing a iiuid under pressure into said chamber, and means associated with said chamber responsive to the pressure of the `fluid therein for imparting tension to said rod.

3. In a warp knitting machine having `a resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing over it, yarn tension sustaining means associated therewith urging said tension rod against the yarns, said means including an enclosed chamber, and means for introducing a iiuid under a predetermined pressure into said chamber.

4. In a warp knitting machine having va resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing-over it, yarn tension sustaining means associated therewith urging said tension rod against the 5. yarns, said means including an enclosed chamber, means for introducing a fluid under a predetermined pressure into said chamber, means for controlling the operation` of the machine, and means responsive to said controlling means for controlling the introduction of iluid into said chamber.

5. In a warp knitting machine having a resiliently displaceable tension rod responsive to variations ofv the pull of the yarn flowing over it, means for vyieldingly supporting said rod, and yarn tension sustaining means associated with said supporting means comprising in combination a spring and a piston and piston chamber arranged to urge said rod in the yarn tensioning direction.

6. In a warp knitting machine having a resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing over it, yarn tension sustaining means associated therewith urging said tension rod against the yarns, said means including a spring, an enclosed chamber, means for introducing a fluid under pressure into said chamber, and means associated with said chamber responsive to the pressure of the fluid therein.

7. In a warp knitting machine having a resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing over it. yarn tension sustaining means associated therewith urging said tension rod against the yarns, said means including a spring, an enclosed chamber, means for introducing a fluid under a predetermined pressure into said chamber, and means associated with said chamber responsive to the pressure of the fluid therein arranged to supplement the force of said spring.

8. In a Warp knitting machine having a resiliently displaceable tension rod responsive to variations of the pull of the yarns flowing over it, yarn tension sustaining means associated therewith urging said tension rod against the yarns, said means including a spring, an enclosed chamber, means for introducing a iiuid under a predetermined pressure into said chamber, and means associated with said chamber responsive to the pressure of the fluid therein, means for controlling the operation of the machine, and means responsive to said controlling means for controlling the introduction of fluid into said chamber.

9. In a warp knitting machine a tension rod responsive to variations of the pull of yarns flowing over it, a support for said tension rod, and means acting on said support to urge said rod in the yarn tensioning direction, said means including a cylinder, a piston slidably mounted in said cylinder, means for introducing a fluid under pressure into said cylinder in one direction, said piston carrying a part exterior of said cylinder, and a spring interposed between said part and said support.

10. In a warp knitting machine having a frame, a yarn tension rod arranged to have the yarns ilow over it, a rock member pivotally mounted on the frame of the machine and arranged to support said tension rod, a cylinder, a piston slidably mounted in said cylinder, and a coiled spring interposed between said piston and said rock member arranged to urge said tension rod against the yarns.

11. In a warp knitting machine having a frame, a yarn tension rod arranged to have the yarns flow over it, means comprising a rock arm pivotally mounted on the frame of the machine and arranged to support said tension rod, and a unit comprising a cylinder, a piston slidably mounted in said cylinder, and a coiled spring interposed between the frame of the machine and said rock arm for urging said tension rod against the yarns, said piston being arranged to vary the force applied by said spring to said rock arm.

12. In a warp knitting machine having a frame a support for a yarn tension rod comprising a rock arm pivotally mounted on said frame, tension rod engaging means at one end of the rock arm, a threaded guide rod pivotally mounted at one end upon said frame and passing loosely through the rock arm, a thumb nut adjustably engaged with the threaded guide rod adjacent its free end, a coiled spring surrounding the threaded guide rod and bearing at one end upon the rock arm, and a unit comprising a cylinder and cooperating piston mounted on said guide rod for movement longitudinally thereof and for relative axial movement, said unit being interposed between said spring and said thumb nut and being arranged to vary the tension of said f spring upon relative axial movement of said "cylinder and piston.

13. In a Warp knitting machine having a frame, an electrical drive and a power circuit for delivering current to said drive, a support for a yarn tension rod comprising a rock arm pivotally mounted on said frame, tension rod engaging means at one end of the rock arm. a threaded guide rod pivotally mounted at one end upon said frame and passing loosely through the rock arm, a nut adjustably engaged with the threaded guide rod adjacent its free end, a coiled spring surrounding the threaded guide rod and bearing at one end upon the rock arm, a unit comprising a cylinder and cooperating piston mounted on said guide rod for movement longitudinally thereof and for relative axial movement, said unit being interposed between said spring and said thumb nut and being arranged to vary the tension of said spring upon relative axial movement of said cylinder and piston, a source of compressed gas and a conduit therefrom to the cylinder, and means associated with said power circuit for causing the delivery of gas from said source to said cylinder when the circuit is opened and for cutting of such delivery and bleeding the cylinder when the circuit is closed.

14. In a warp knitting machine having a yarn tensioning rod over which the yarns now toward the knitting devices, means for movably supportmg said rod, power means for driving said machine and means for controlling said power means to start and stop the machine, the combination of spring means for imparting a predetermined resilient force to said rod supporting means to apply a corresponding tension to the yarns, and means responsive to the operation of said controlling means for applying an additional resilient force to said rod supporting means.

l5. In a warp knitting machine having a yarn tensioning rod over which the yarns ow toward the knitting devices, means for movably supportmg said rod, power means for driving said machine and means for controlling said power means to start and stop the machine, the combination of spring means for imparting a predetermined resilient force to said rod supporting means to apply a corresponding tension tothe yarns, and means responsive to the operation of said controlling means for applying an additional resilient force to said rod supporting means, said '7 controlling means including a manually operable device and means for delaying the effect upon said power means of an operation of said manually operable device.

16. A method of preventing the formation of 5 stop marks in the operation of 'a warp knitting machine having a resiliently mounted thread tensioning rod responsive to variations ofthe pull of the yarns flowing over it which comprises maintaining a predetermined range of tension on said rod during operation of the machine/increasing the tension applied toV said rod as the machine is stopped and restoring said tension to said predetermined range when the machine isl started up again.

CLARENCE J. BROWN. TI-I'EODORE W. SCHWANDA.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,998,473 Welch s Apr. 23, 1935 2,375,316 Moessinger 1...- May `8, 1945 2,451,499 Lambach s Oct. .19, 1948 2,486,525 Fuhrer ..v f Nov. 1, 1949 

